1. Field of the Invention
The present invention relates to a television set, and more particularly to an apparatus for reducing a vibration of a television set which can reduce a vibration and an interference produced by a low frequency resonance between a speaker and a casing holding the speaker therein.
2. Description of the Prior Art
Generally, a speaker of a television set is an apparatus for transforming an electric signal to an audio signal and includes a magnetic circuit, a voice coil, and a vibration system.
FIG. 1 is a partial sectional view of a television set including a speaker 5. Referring to FIG. 1, a diaphragm 4 for generating a sound pressure is attached to speaker 5. A front casing 1 is formed at a predetermined position thereof with a duct 3 for guiding a sound reproduced by speaker 5 to the outside thereof. Speaker 5 is secured to one end of duct 3, and a speaker grill 2 is installed at the other end of duct 3. Reference number 6 indicates buttons for selecting operation modes of the television. In general, speaker 5 has a capacity of 3 Watts.
FIG. 2 is a perspective view of front casing 1. Referring to FIG. 2, a couple of rails 14 for mounting a PCB (not shown) are installed at a bottom plate 12 of front casing 1. Front casing 1 is formed at a front portion thereof with a plurality of thruholes 9 for inserting buttons 6.
FIGS. 9 and 10 shows an acceleration and a displacement of speaker 5 secured to front casing 1 in response to a frequency. As shown in these graphs, the speaker has a resonance frequency of 168 Hz in which the speaker resonates with a maximum amplitude. Also, in FIG. 11, a sound pressure level detected from outside of the television set including speaker 5 in response to a frequency is represented by a continuous line.
As shown in FIG. 11, the television set represents a maximum sound pressure level at 216 Hz, and accordingly, the resonance frequency of the set is 216 Hz.
However, this low frequency resonance generates a relatively high vibration, so an interference in the sound and the image is frequently produced. So, the sound pressure generated from the television set at 216 Hz is caused mainly by the vibration of the television set itself.
The vibration is transmitted along front casing 1 so as to vibrate a couple of rails 14, buttons 9, and various components installed in the television set. This vibration may disturb a viewer.
Also, since the PCB mounted at the couple of rails 14 vibrates, in some cases, the coil at the PCB may by disconnected. Furthermore, due to the vibration of buttons 9, an interference in the image of a monitor or a change in the operation mode of the television set is produced.